Brenda Beust Smith photo
One of my two Rosedown gardenias died. This was before the snow. Both were doing great. They both bloomed beautifully and have for the past four or five years.
And then one died. Overnight it seemed. Beautiful one day, dead the next.
I know all the reasons why plants won’t bloom. Maybe, I reasoned, there are multiple reasons too why a seemingly-perfectly-healthy plant would suddenly die practically overnight.
Surely, I reasoned, it might have to do with the root system. So I asked my soil guru, John Ferguson of Nature’s Way, if he could list some possible causes — beside below freezing temperatures, that is.
He had plenty:
1) Too much water. We had excessive rains during fall. Water fills up the pore spaces in the soil forcing the air (oxygen) out.
2) Beneficial microbes require oxygen. Most pathogenic fungus diseases prefers low oxygen conditions. They can multiply quickly, wiping a plant out in a few days.
3) Desirable aerobic decay of organic material (vital for plants) requires oxygen. Lack of oxygen causes anaerobic decay, also known as fermentation which produces alcohols. It only take one part per million alcohol to kill roots and plants quickly die.
4) Anaerobic decay also produces organic acids that can quickly kill a plant. Wanna try a soil smell test? Some common ones and their odors are:
• Acetic acid: vinegar smell, loss of N2 and P, alcohols present
• Butyric acid: sour milk smell, alcohols present
• Valeric acid: vomit smell, alcohols present
• Putrescine acid: rotting meat smell, alcohols present
Or, if you smell . . .
• Ammonia: implies an immature decomposition (phytotoxic) and a loss of nitrogen
• Rotten egg (H2S): implies an immature decomposition (phytotoxic) and a loss of sulfur
5) Both commercially available mulches and chemical fertilizers might be the culprits. Too-green wood or additives in mulches and salts in fertilizers might cause problems. Best to shop for both mulches and fertilizers from a nurseryman you trust.
6) Wet soil compacts easily when walked upon, forcing out the oxygen. Roots often extend far beyond the drip line of a plant. Hence repeatedly walking on a path could create local conditions that allows a pathogen to grow and enter the root system.
7) Pest nematodes thrive in very wet soils and can quickly weaken a plant that allows other factors or combinations there of to kill it. Beneficial nematodes require oxygen.
8) Some contact herbicides that can kill in a few hours. Commercial strength vinegar even though it is organic, is an example.
9) Any extreme change from hot or cold or cold to hot will injure some species.
John adds that most of the time, plant problems are the result of overwatering or too much water. I absolutely agree.
What to do? Put your plants in raised beds. (My gardenias were at ground level.) We have spring and fall monsoons. It’s the only answer.
If you have any plants that just “up and died” and you later found out why, let us know!
SAVE THE DATE: Here’s a great upcoming event (especially given our freezing temperatures): “If You Can’t Stand the Heat, Get outta the Garden: Hot Plants for Hot Climates” by Tony Avent, owner of Plant Delights Nursery and Juniper Level Botanic Gardens in Raleigh, NC.
Tony will advise us on great plants for our heat (which is far more of a problem than our cold) on Tues., Jan. 12, 10 a.m. at St. Martins Episcopal Church Parish Hall, 717 Sage at Woodway. The free program is a Nancy Stallworth Thomas Horticulture Lecture.